Motor



Jan. 4, 1944.

w.v w. PAGE-r MOTOR Filed Aug'. l, 1941 lg@ ven/Zar: 20v/'n Zd Pacgei'.

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mm www Patented Jan. 4, 1944 MOTOR Win W. Paget, Michigan city, Ind., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application August 1, 194i, serial No. 405,067

(ci. 1v1-252) 14 Claims.

This invention relates to motors, and more particularly to improvements in devices for draining the motor -casings of electric motors, such as, but without limitation thereto, the electric driving motors of rotary drilling apparatus.

The preventing of injury by liquids such as lubricant to the insulation of electric motors is a substantial problem, and in motors which may be now inclined in one direction and now in anvother and which may be utilized in wet places the problem is intensified. The :problem is further made more difficult when explosion-proof construction is necessary and also, when, to insure cooling, there is circulation of cooling mediummoisture-laden air-so that there are likely to be created conditions in a peripherally sealed rotor and eld chamber which tend to induce the entry of fluid thereto along the rotor shaft.

An object of this invention is to provide improved drainage means for an electric motor. Another object is to provide improved means for draining the motor casing of a rotary drilling apparatus, Still another object is to provide improved drainage means for a drilling apparatus of the type wherein a rotary motor is employed for rotating a drill bit and which embodies a tube extending axially through the motor shaft for conducting cleansing fluid to the drill bit. Still another object is to provide improved drainage means for the motor casing of a rotary type drill- .ing apparatus, said drainage means including a plurality of drainage ports in the motor casing connected to a low pressure area for effecting a uniform suction of fluid from each of the ports, whereby, whether up or down drilling is being performed, adequate drainage may be assured. Still another object is to p-rovide improved means for` draining a chamber at a plurality of points by directing a flow of air rpast each of the points and thereby creating a uniform suction at such points. Other objects and advantages of the invention will, however, hereinafter more fully appear.

1n the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practice.

In the drawing:

Fig. 1 is a view in central longitudinal section taken through a drilling apparatus in which an illustrative embodiment of the invention is incorporated.

Fig. 2* is an enlarged fragmentary sectional vView showing details of the improved drainage means.

Fig. 3 isa sectional view showing details of the drainage connections at one of the ports, taken on line 3 3 of Fig. 2. l

In this illustrative embodiment of the invention the improved drainage means, generally designated l, is shown associated with the motor of a rotary type drilling apparatus, generally designated 2, which is of the same general char- -acter as that disclosed in my copending application, Serial No. 268,792, filed April 19, 1939, which has now matured into Patent No. 2,288,541, patented June 30, 1942. It will be evident, however, that various features of thel invention may be associated with rotary apparatus of various other types and with motors for other than drilling purposes.

The drilling apparatus 2 includes a drill bit rotating motor 4 carried by a rear support '5. The motor herein shown is of the high speed electric type, and includes a casing 6 provided with front and rear heads 8 and 9 held in assembled relation with respect to the casing by usual tie bolts II. The motor has a usual field l2 `and an armature rotor I4, the latter having a shaft It which is supported in bearings I6, I6, suitably supported in the motor heads. Surrounding the motor casing is a cyclindric shell I8 fitting cylindric portions of the motor heads and held between shoulders on the heads by the tie bolts, and this outer shell cooperates with the motor casing to provide an annular space I9 surrounding the motor casing. The tie bolts I I extend longitudinally through this space as shown in Fig. 1. Secured to the front motor head by the tie bolts is a plate 2l providing an abutment surface 22 for holding the outer race of the front bearing It in place in the motor head, and secured to the plate 2l, as by bolts 23, is a housing 24 within which a fan 25 is arranged and secured in any suitable manner to the motor rotor shaft, The fan 25 acts to draw cooling air through radial passages 21 in the rearward portion of the outer shell I3, through the annular space I9 between the motor casing and the outer shell, and through passages 29 and 30 in the front motor head and the plate 2l respectively, into the housing '124 whence it is discharged by the fan outwardly through radial discharge passages 32 formed in the housing.

Threadedly connected to the rear end of the rotor shaft I5 is a bearing retaining member 33, and the inner race of the rear bearing I6 is held between a member 34 engaging a shoulder on the shaft and the member in the manner shown. The inner race of the front bearing It is held in place in a similar manner by a memm ber 35 threaded on the .forward portion Vof the rotor shaft and a member 36 engaging a shoulder on the shaft. Attached to the forward end of the rotor shaft is a chuck 38 for receiving the shank of a hollow drill tool (not shown). The rotor shaft has an axial bore d!) extending therethrough, and arranged in this bore is a fluid conducting tube tl, the latter being somewhat smaller in diameter than the bore to provide clearance between the tube and the shaft. rI'he tube 4| is threaded at its rear end into an opening 42 formed in a member 3 which is secured, as by bolts 44, to the rear support 5. The opening l2 communicates with a passage l5 formed. in the member 43 for connecting the interior of the tube with a suitable source of cleansing'nuid supply, herein to a source of' liquid underpressure. Arranged on the rear end of the rotor shaft is a seal 4l cooperating with an annular flange 43 for preventing, to a substantial ext-ent, any liquid leaking around the end of the tube il into a chamber l), from flowing tothe rear bearings IB and into the interior of themotor casing. The chamber 50 is also connected. by a passage 52 with a vent passage 53 in the rear support 5, so that any leakage to the chamber may drain to atmosphere.

It will be noted that the interior of the motor casing is connected, though through a restricted passage, through the clearance between the rotor shaft and the front' motor head and through the front bearing i6 to the fan housing at a point of substantial fan suction. The suction through this space from the interior ofthe motor casing tends, at least, to cause a subatmospheric pressure to exist within the casing, and the tendency for liquid to pass from the chamber 5B into the rear end of the casing is increased. In order to drain from the casing any liquid entering the latter, the improved drainage means I communicating with the interior of the casing at its opposite ends is provided, Itwill be appreciated that if drainage ports alone were provided opening into the annularspace I9, dust andV moisture entering this annular space from the openings 21 would be drawn into the motor casing since the pressure f withinthe latter would be lower than that in the annular space. The improved drainage means comprises connecting elements 55 threaded into openings in the motor casing E, and bores 56, opening through the inner ends of the connecting elements into the interior of the casing, are connected through transverse bores El into communication with annular grooves 53. A tube section 6l! extends from a point adjacent one opening 2l in the outer shell to the element 55 at the'- rear end of the motor casing where it communicates through an opening in the element with its annular groove 53. This tube section is bent-so that its rear end points in the direction of the flow of cooling air through the annular space I8. By reason of this, dust orother particles pulled into the annular space will pass by theopeny end ofthe tube due to their inertia, and substantially clean air will be conducted through the tubeto the annular groove 58. Another tube section 5l connects the annular grooves 53 of the elements 5.5 in communication with each other. A third tube section 83 connects the groove 5B of theY element 55 at the front end of the motor in communication with a point adjacentV the fan where the suction is greatest.

As the motor is operated to drive the drill, the fan 25rotates at a high speed and creates a suctionat the front end of the tube 62. This suction causes air to-ilow through the tube 60 to the annular space 58 in the rear element 55, through the tube 6l to the groove 58 in the front element and through the tube 62 into the fan housing. The rush of air through the annular grooves 58 causes a suction to be created in the bores 55 and 51 which communicatewith the interior of the motor casing. The suction at the points of communication of the drainage connections with thev motor casing will be. at least substantially as great as that through clearances at the front end of the casing around the rotor shaft, and any liquid entering the motor casing will be withdrawn through the drainage connections as it gains access to the latter. Since the rear end of the tube G points in the direction of flow of cooling air through the space between the outer shell and the motor casing, particles of foreign matter are carried: past the open end of the tube and the air passages in the drainage means are maintained free of dirt, It will of course be understood that the improved drainage means may be employed for draining any part of the drilling apparatus or for draining other types of apparatus.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modied and embodied in various other forms without departing from its spirit or the scope. of theV appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. A drainage device for a motor enclosed within a casing including, in combination, a fan arranged outside of said casing and driven by the motor, fluid conducting means subjected at one end to the suction of said fan and connected at its other end in communication with the atmosphere, and means connecting the interior of the motor casing in communication with said fluid conducting means between the ends of the latter.

2. A drainage device for a motor enclosed within a casing including, in combination, a fan arranged outside of said casing and driven by the motor, a connecting element having a bore opening into the interior of the motor casing and communicating with an annular groove at the outer surface of said casing, fluid conducting meansv for connecting said annular groove in communication with a point adjacent the suction side of said fan, andfluid conducting means for connecting said annular groove to atmosphere at a point spaced from saidfan.

3. in an apparatus of the character described, the combination. comprising a motor including a motor element enclosed in a casing, means including a fandriven by the motor for circulating cooling air along the outer surface of the casing, and motor drainage means including fluid conducting means having communication between its ends with the interior of the motor casing at the bottom of the motor and subjected at one end to the suction of the fan for effecting a forced flow of fluid from within the motor casing thereby to draw out any liquid leaking into the motor.

4. In an apparatus of the character described, the combination comprising a motor including a rotor supported for rotation Within a casing, a fan arranged outside of said casing and driven by said rotor forv circulating cooling air over. said motor casing, and motor drainage means including fluid conducting means extending along the outer surface of the casing vand having communication between its ends with the interior of the motor casing below said rotor and subjected at one end to the suction of said fan for effecting a forced flow of fluid from within the motor casing thereby to draw out any liquid leaking into the motor.

5. In an apparatus of the character described, the combination comprising a motor having a rotor supported for rotation Within a motor casing, a fan arranged outside of said casing and driven by said rotor for circulating cooling air over said motor casing, and means for eilecting a iorced flow of iiuid from within said motor casing including a tube subjected at one end to the suction of said fan and communicating at its opposite end with atmosphere at a point spaced from said fan, and means for connecting the interior of said motor casing in communica tion with said tube.

6. In an apparatus of the character described, the combination comprising a motor having a rotor supported for rotation within a motor casing, -a ian driven by said motor for circulating cooling air over said motor, and means for draining said moto-r casing at a plurality of po-ints including connecting elements having bores opening into the interior oi the motor casing at said points and communicating with annular grooves, and fluid conducting means for connecting said annular grooves in communication with a point adjacent the suction side of said fan for connecting said annular grooves to atmosphere at a point spaced from said fan.

7. In an apparatus of the character described, the combination comprising a motor enclosed within a casing, said motor having a rotor supn ported for rotation within said motor casing, a shell surrounding said motor casing and providing an 'annular space therebetween, a fan driven by said rotor for circulating cooling air through said annular space, and means for draining said motor casing including iiuid conducting means arranged in said annular space and connected in communication with the interior of said motor casing, said lluid conducting means also communicating with the space closely adjacent to the suction side of said fan for effecting a withdrawal of fluid from said motor casing.v

8. In an apparatus of the character described, the combination comprising a motor enclosed within a casing, said motor having 'a rotor supported for rotation within said motor casing, a shell surrounding said motor casing and providing an annular space therebetween, a fan con nected to said rotor at one end of said motor casing for circulating cooling air through said annular space, and means for draining said motor.

casing including a tube communicating with the space closely adjacent the suction side of said fan and extending through said annular space to communicate with atmosphere at the opposite end of said motor casing, and means connecting the interior of said motor casing in communication with said tube.

9. In an apparatus of the character described, the combination comprising a motor enclosed within a casing, said motor having a rotor supported for rotation within said motor casing, a shell surrounding said motor casing and providing an annular space therebetween, a fan connected to said rotor at one end of said motor casing for circulating cooling air through said annular space, and means for draining said motor casing including a tube communicating with the space closely adjacent the suction side of said fan and extending through said annular space to communicate with atmosphere at the opposite end of said motor casing, said tube being bent so that its end communicating with atmosphere extends in the direction of flow of cooling air through said annular space, and means connecting the interior of said motor casing in communication with said tube.

l0. In combination, a motor enclosed within a casing, said motor including a rotating element having a shaft supported for rotation by said motor casing, a fan connected to said shaft adjacent one end of said motor casing for circulating cooling air over the outer surface of said casing, and means for creating a partial vacuum within said motor casing, said last mentioned means including a tube communicatin-g at one end with the space closely adjacent the suction sideY of said fan and extending along the outer surface of said motor casing into communication with the atmosphere near the end of said motor casing remote from said fan, and fluid conducting means connecting the interior of said motor casing in communication with said tube between the ends of the latter.

11. In combination, a motor enclosed within a casing, said motor including a rotating element having a shaft supported for rotation by said motor casing, a fan connected to said shaft adjacent one end of said motor casing for circulating cooling air over the outer surface of said casing, and means for creating a partial vacuum within said motor casing, said last mentioned means including fluid conducting means subjected to the suction of said fan and communicating with the atmosphere at a point spaced from said fan, and means connecting the interior of said motor casing in communication with said uid conducting means between the ends of the latter.

l2,` A drainage device for a motor enclosed within a casing including, in combination, fluid conducting means extending along the outer surface of the motor casing, means for causing fluid to flow through said iiuid conducting means, and means connecting said fluid conducting means between itsends in communication with the interior of said casing so as to produce a suction within the latter.

13. A drainage device for a motor enclosed within a casing including, in combination, fluid conducting means extending longitudinally of the motor casing, means for causing a stream of air to now through said fluid conducting means, and means including passage means extending substantially transversely to said uid conducting means for connecting the latter between its ends in communication with the interior of said caslng.

lll. In combination, a motor having a casing and an internal chamber and a rotor rotatable within said chamber and means for conducting a cooling iluid longitudinally of the motor in the space between the outer surface of the casing and the bounding surface of the chamber, means turning with said rotor for effecting a flow of cooling fluid through said conducting means, and means for draining said chamber including a conduit extending through the cooling uid conducting means and having one end subjected to a suction created by the ow of cooling iiuid and its other end open, said conduit connected at a point intermediate its ends with said internal chamber at a low point therein.

WIN W. PAGET' 

